VELIKIN, V. L.; VELIKINA, Yu. V. Widths of sets of functions of discrete variable. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 48, n. 10, p. 1311–1320, 1996. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5216. Acesso em: 5 dec. 2025.